Grating structure



April 1943- H. H. BUNKER 2,317,174

GRATING STRUCTURE Filed Feb. 28, 1941 INVENTOR.

10 4/ if) 50 10 6 flerzri/Zfiunlar Patented Apr. 20, 1943 UNlTED STATESPATENT QFFICE GRA'IING STRUCTURE He bert H- un J sey City, N- J assignorto e ow Ste Fl o Compa rsey City. J-, a o p r tion of New Jers yAppiication February 28, 1941, Serial No. 381,014

3 a m lCl- 189* This invention relates to grating structures for openflooring and particularly to grating suitable for walkways, runningboards, catwalks and the like.

Among the objects of this invention is to provide a grating structuresuitable for walking upon under conditions which are ordinarilyconsidered as requiring the exercise of caution and the need of completeconfidence in the underfoot security provided by the walking surface.While a grating surface composed of metallic bars spaced from oneanother makes a good floor surface, the general utility of such asurface construction is sometimes restricted because the edges of thebars become smoothened by erosion under certain conditions of use.Gratings Sub-.- ject to weathering, Walkways about industrial plants andon shipboard, and running boards and steps on freight cars are examplesof grating surfaces which are particularly subject to une desiredalteration of their surfaces from rusting and other causes of erosion.An object of the i nstant invention is directed to producing a suitablegrating for these and kindred uses which possesses slip-proof qualitiescapable of retention as part of the structure throughout its life andunder severe conditions of erosion.

In the grating of the present invention, the bars which correspond tothe longitudinallyrextending girder bars on the common grating areinterrupted by a series of cut-out portions which operate to eliminatethe continuity of the upper edges of these bars and thereby materiallydiminish the hazard of slipping inherent in a continuous straight bar.At the same time the frictional coefiicient of the entire gratingsurface is further increased by projections or offsets which extendlaterally of the girder bars and above the surface defined by the uppersurfaces of their sup-. porting girder bars. The drawing shows by way ofillustration a preferred embodiment and the principle of my inventionand what I now consider to be the best mode for applying that principle.Other embodiments of the invention employing the same principle may beused and structural changes made as desired by those skilled in the artwithin the spirit of the appended claims and without departing from thepresent invention.

In the drawing,

Fig, l is a plan of a section of the grating.

Fig. 2 is a side elevation on line 22 of Fig. 1.

Fig. 3 is an end elevation on line 3-3 of Fig. 1.

The grating is an assemblage of longitudinallyextending girder bars Illspaced from one another and secured together by cross-bars l I. Thegirder bars are made from strip material, rectangular in cross-section.They are designed for load bearing purposes and are supported by beamsupon which they rest, or upon the crossbars, as will be explainedhereinafter. The girder bars of the instant invention have ofisets orpro- J'ections l2 which are punched out of the flat strip which formseach girder bar. It is apparent that the configuration of these punchedcut projections may take various forms, it being important, so far asthe present invention is concerned, that they provide oifset surfaceswhich extend laterally to the girder bars and also above the straightedges of the girder bars from which they are punched.

I he punching is accomplished by a cutting and die operation whichsevers the offset l2 from the girder bar along lines [3, M and I5 (Fi2). Immediately upon severance, or by independent following operations,the offset is bent out from the girder bar, either in a single twistbend or by a double bending. As shown in the drawing, it is preferablybent along two lines which converge with respect to each other in theplane of the bar. One of these lines aa,, Fig. 2, is at an angle to thevertical and marks the line of folding between the girder bar and theoffset. Its angularity causes the offset to be projected above thehorizontal plane of the portions l6 of the girder bar which remain inalignment as discontinuous upper edges of the girder bar, as illustratedin Fig. 2. The amount of elevation of the offset above the top edges I6is a function of the angue larity of the fold line aa with the vertical,and this may be varied in accordance with the res s desire to be a e eit b n un r to that the drawing is for the purpose of illustratns theprin e o y.

he s nd i e f mm b .s1 a d b tw the fi st ne of ld a o and the free nd ot e Offs t. T is s ond. l ne. o f l 2- is ao u a l disposed withreference to the top edges of the ofiset and has the effect of bringingthe portion of the offset adjacent its free end into a horizontalposition so that all of the upper edges of the offsets outward from theline bb are in a common horizontal plane above the plane of the portionsI6 of the girder bars, as illustrated in Figs. 2 and 3.

It is apparent from this construction that the offsets provide, togetherwith the remaining portions of the girder bars, a broken ordiscontinuous undulating surface which has a large number of relativelysharp edges and corners at right anboard gratings and is a desirablematerial.

gles and oblique to one another. The effect of this is that the bearingsurface under the foot of a pedestrian is broken in a sufficient numberof places adequately to obstruct slipping in any direction. The girderbars provide longitudinal edges l1, l8, which prevent side slipping; theoffsets provide edges I9, 20, at right angles thereto for preventingslipping along the girder bars and also oblique edges 2|, 22, 23 and 24with the girder bars which restrain slipping in those directions.

istics of the grating surface. It is apparent that the offset may bebent in a continuous curve either in whole or in part instead offormingtwo distinct planes, as shown in Fig. 1. Also, if desired, everyalternate girder bar could be placed in a direction reversed to thatshown in the draw ing whereby the pattern produced by the difierentdispositions of the offsets would be different from that shown in Fig.1, although similar antislip characteristics would still be present.

Steel is commonly used for forming running Qrdinary wear of sharp orsquare edges results from abrasion through constant use, but rust flakesoff and pits the metal and the disintegration caused thereby'quickly'rounds off all natural edges which normally retard slipping.Superposed bosses or impressed indentures designed to prevent slippingalso have their purpose adversely affected by the same cause. Thepresent construction, while being exposed to the same deleterious wear,nevertheless will retain high non-slipping characteristics because ofthe permanency of its floor pattern;

The features of the invention thus far described are applicable for usewith cross-bar gratings having cross-bars in which the crossbars havetheir upper edges in the same plane as the upper edges of the girderbars. It is intended that in such a structure the offsets be made in themanner and for the uses previously described. Particularly withreference to the use of the invention for fabricating running boards forfreight cars, there is advantage in providing the cross-bars in themanner illustrated in the drawing. In this construction the cross-barsare notched at intervals (at 30) along their top edges and the girderbars are notched at intervals (at 3|) along their lower edges so thatthe notches of each set of bars may snugly engage the bars of the otherset of bars in a double tongue'and groove joint. As illustrated in Figs.2 and 3, the depths of the notches are so proportioned that after thebars are engaged the cross bars extend below the girder bars. Thesecurity of the engagement may be increased by providing dovetailed ends32 at the bottoms of the notches in the girder bars which receivematerial forced therein from the cross-bars as the cross-bars are forcedinto engaged. With the lower edges of the girder bars elevated above Theend edges 25, 26, 21 and 28 add, to the tractional effect and anti-slipcharacter-' the lower edges of the cross-bars, space is provided beneaththe grating structure which prevents entrapment of water or othermaterial in the interstices of the grating when the grating is laid upona flat solid surface.

When exposed to rainand salt air, the metallic grating designed for useas a running board is likely to have its usefulness impaired byexcessive erosion sooner than by either abrasive wear or impact effectsproduced by walking thereon. This is because such a grating usually hasmore material in it and therefore possesses more strength than isactually required for its service. While its margin of strength issufficient to counteract any weakness which may develop from loss ofmaterial through corrosion, if the edges become rounded and itsslipperiness increases, its efiicaciousness is seriously impaired; Thegrating of the present invention discounts the effect of the wear uponthe edges by providing a large number of edges and discontinuous bars inthe walking surface with some of these bars elevated with respect to theothers.

What is claimed is:

1. A grating structure formed of intersecting and joined girder bars andcross-bars, said girder bars; having laterally extending ofl'sets spacedat intervals along the girder bars and extending upwardly above the'planeof the upper edges of the girder bars to form an undulating floorsurfacefor the grating structure, said offsets being bent out from thegirder bars on substantially vertical lines of fold.

2. A fioorgrating structure comprising intersecting and joined girderbars and cross-bars pro viding open spaces in the floor area of thegrating structure, each of said girders having a discontinuous upperedge provided by a series of notches, a plurality of projectionsextending sidewise from said girder bars and terminating in free ends inthe spaces between adjacent girder bars, each projection being anintegral part of a girder bar to which it is joined at one of the edgesof a. notch and said projection having a portion thereof extending abovethe plane of the upper edges of the girder bars and substantially atright angles to the longitudinal direction of the girder bars. 7 a 3. Ananti-slip open grating structure comprising intersecting girder bars andcross-bars standing on edge and joined together at their intersectionsby notches in the respective bars, said bars having their flatwisedimensions perpendicular to the plane of the grating, means carried bysaid girder bars for providing an undulating contour for the top surfaceof the grating, said means comprising cantilever projections bent fromthe girder bars and having their free ends projecting into the spacesbetween the girder bars and above their floor surfaces so as to provideanti-slip elements in the top level of the grating within the spacesbetween the girder bars.

HERBERT I-I. BUNKER.

